Trialkyl phosphines for diesel fuels



at e -e 96 a a v 2,368,866 uNlTEos A Es PATENT OFFICE- messes TBIALKYL rnosrlmms FOR DIESEL FUELS No Drawing. Appiication October 22, 1941,

Serial No. 416,048

- ,3 Claims. (01. 44-57) This invention relates to fuels 'ior internal com- A. Berle. Jahresber, Fortschr. Chem. 1855, 590. I bustion engines of the Diesel or compression ig- Sodium-phosp r us 5 is tr with nition type, and more particularly relates to the I yl iodide. d-

improvement of such non-viscous hydrocarbon B, A. Cahours and 'A. Hoimann, Ann. 104, 1,

"iuels by the addition thereto 01' a characterizing- 1 (1857). The reaction of phosphorous trichlosc nt. V ride with a'. solution of-diethyl zinc in ether I In Diesel engine operation, a liq id. fuel is ingives the zinc chloride salt of triethyl ph jected into a combustion chamber and ignited by phine. The free phosphine is obtained by discompression; In order toobtainmaiimum eflltillation from alkaline solution. ciency. the delay period between the instant of 10. C. A. W. Hofmann, Ann. Sup]. 1, 4 (1861-2).' A. injection and theinstant oi ignition should be Cahours,--Ann. 122, 329 (1862). Phosphorousshort. Improperly delayedi ignition gives rise to 1 zinc alloy, or a mixture of phosphorous and the phenomena known as "knocking" due to imzinc is treated at elevated temperature and I proper coordination of combustionand. cylinder 7 pressure with ethyl i characteristics; By accelerating the ignition u D. Drechsel and Finkelstein, Ber. 4, 352 (1871). point of Diesel fuel it is possible to lower the Zinc hydro n ph p e, from diethyl Zinc compression pressure, which will insure spontaand phosphine, is treated with ethyl iodide to neous ignition without combustion shock, there-' ive the hydriodide of 'triethyl'phosphine. by increasing the ease of starting andsmooth E'. A.'W. Hofmann,Ber.'4,205, 3'72 (1871). Phosness with which combustion takes place. a phonium iodide treated with ethanol at 180 As iswell known to those more iamiliar with 0. gives the, hydriodide of triethyl phosphine. the art, various compound hav b g d .F. Hibbert, Ber. 39, 160 (1906). Ethyl magnewith the capacity to improve the ignition quality slum bromide treated with phosphorous triof Diesel fuels;- Small amounts of such m; bromide followed by dry distillation gives tripounds incorporated in the fuel act as ignition ethyl Dhosphine. accelerators. By such means, the better mas G. W.,C.' Davies, et al. J. Chem. Soc. 1929 38,. oi Diesel fuels are improved, and the l w: grad 1262; 1930, 2298; 1931, 575; 1932, 2880; 1933, fuels are improved so as to have r at f m 1043; 1935, 462. The method is essentially that The present invention is predicated n t of the preceding reference, the main excepdiscovery that the ignition delay period of than being the method of decomposing the viscous hydrocarbon fuel Oils used in Diesel type 1 risnard rea ti n ixture a o y of t engines, is decreased substantially by the addi- P "\J, thereto or malkylphospmne- The trial- ;As examples of the trialkyl phosphines, we have phospmnes are m characterized y prepared triethyl phosphine by the method prothe general formula posed by Hilpbert (reference F), and tributyl B! phosphine by the method proposed by Davies et 1 al. (reference (3-) and these procedures, which are '7 typical methods for preparing compounds of the v n, i general class contemplated herein, are described V e r inthe following illustrative exam les: I wherein, R1, R2, and R: represent .alkyi radicals p and by R1, R1, and'Rs Exams: I may same or different alkyl groups. Typ-- i ical alkyl radicals which may be present in the Tnethfl i fllkyl D Dhines contempla i meth- In'a three-necked flask of suitable'size, fitted r L pfl. ow uwLse -butfl. with a stirrer, reflux condenser and dropping tunnel, were placed 35.4 parts'of anhydrous ethyl s inventiim plates Diesel fuels conether and 4.86 parts of magnesium turnings.- To

mm; tri-alkyl phosphines oi the ioregoingi the magnesium and etherwere gradually added W9 8- coniiemlllfl-ted 8-180 yi invention-i8 21.8 parts of ethyl bromide. To the cooled an improved method of acceleratlngthe ignition Grignal-d solution were gradually added 6.0 parts of a non-viscous hydrocarbon fuel oil in oomof phosphorous tribromide (prepared by the pression ignition engines, said method being method inOrganicSy'ntheses-vQL XIII, pg. 21)

characterized y the-step or admixing a t'lmkyl dissolved in 249mm of anhydrous .eth

palli'osphina with the fuel prior to its in. reaction mixture was transferred to a distilling Various methods of preparation of "flask was then surrounded with an oil bath and pholpllines are known to tlioce'slzillell in the art. the trietllyl phosphine driven, out by gradually Reierence to the literature provides the follow. raising the oil bath temperature to more. Care 'inglistoi'typical-methods: oo'wastakentopreventexposureoitheproductto flask and the ether was distilled. 'nle'dlsunl g catalytically cracked No. 2 fuel oil, which has an A. P. I. gravity of 28.8, flash point of 200 R,-

blend was determined by comparison with a standard reference fuel in a converted C. F. R.

2 I the air. This ditillate was found to be 43-per cent. trlethyl phosphine. Y

' Examrr: II

' Tributyl phosphine In a three-necked flask of suitable size, fitted with-stirrer, reflux condenser and dropping funnel were placed 14.2 parts of anhydrous ethylv ether and 2.5 parts of magnesium turnings. 13.? parts of butyl bromide were added gradually. .To the cooled Grignard solution were slowly added 6.8 parts of phosphorous tribromide (prepared as in Example I above) dissolved in 4.0- part of' anhydrous ether. The reaction mixture was refluxed for thirty minutes and then cooled to C. A solution of 13.0 parts of ammonium ing at 95 C.-105 C. at 8 m. m. collected as the product. The yield was 5% per cent. of the theoretical. I

The efiectiveness of the trialkyl phosphines in improving the ignition qualities of Diesel fuels is 1 demonstrated by comparative results of a fuel blank and a fuel blend. The fuel used was a aniline point of 122 F., and a cetane number of 33.0. The ignition quality of the fuel and the fuel engine using the ignition delay method. The value obtained in this test "is expressed as the cetane number which is the per cent. by volume of octane and alphamethyl naphthalene having the same combustion characteristics as the sam ple under test (Reference: Proc. Am. Soc. Testing Materials, V01. 35, I, 418 (1936) Typical trialhyl phosphines, triethyl phosphine, and tributyl phosphine, prepared as described above, are illustrative of the class of compounds contemplated here as ignition accelerators.

The efiectiveness of such pounds in the aforesaid non-viscous hydrocarbon fuel oil is shown,

in Table r given below:

K Tears 1.

C Per cent 1 Inca-ems Compound added (by wt.) Came in octane added blend No.

37. 5 w 4. 5 36. 9 .r 3. U o 34.0 J w 1.0

It appears the efiective. as amass, to improve the ignition ual- 5 'the cetane number of the t the triaryi phosphines not ity of representative non-viscous hydrocarbon fuel oils. For example, a saturated solution, containing less than 2 per cent. of triphenyl phosphine in a typical Diesel fuel actually decreased therefore, is restricted to the trialkyl phosphines.

For the purpose of this invention, the trialkyl phosphines contemplated herein may be used in amounts of from about 0.1 per cent. to about 5.0 per cent., and preferably from about 0.25. per cent. to about 2.0 per cent.

It is to be understood that the foregoing examples are illustrative only and not to be interpreted as in any way limiting this invention. Similarly, it is to/be understood that the terms Diesel fuel," Diesel type fuel,.'f.hydrocarbon fuel oil," etc., as used herein are inclusive of all types of non-viscous hydrocarbon fuel oils in- We claim:

1. The method of operating an internal-cor. bustion engine of the compression ignition type wherein a'fuelis injected into compressed air in the engine cylinder and ignites spontaneously therein, which com-prises injecting into the compressed air in the engine cylinder a liquid hydrocarbon fuel which would normally cause knocking due to delayeddgnition, and admixing with the iuelprior to such injection from about 0.1 per cent to about 5.0 per cent., to shorten the ignition delay period or said fuel, of a compound represented by thegeneral formula -wherein R1, R2 and R: represent allryl radicals.

2. The method of operatingan internal-combustion engine of the compression ignition type wherein a fuel is injected into compressed air in the engine cylinder and ignites spontaneously therein. which comprises injecting into the com- I pressed air in the engine cylinder a liquid hydrocarbon fuel which would normally cause lmociz- 45 due to delayed ignition, and ads with the fuel prior to such injection fro about 0.1

per cent., to shorten th tion delay period of said fuel, to about 5.0 per cent., of triethyl'phes phine. 5Q .3. The method oioperating an lute-com oustion es of the compression ignition type wherein a fuel is injected into compressed air in engine cylinder and ignites spontaneously therein, which comprises'injecting into the comcarbon guel which would normally cause knocking due to delayed ignitio and admixing with "thefuel, prior to such injection irom about 0.1

1 per cent., to. shorten the ignitiondelay-period of m said fuel. to about 5.0 per cent. of tributyl phos- .phine. .5" 'W 7 v Mime.

- g Jon. MQCRAC.

fuel. Our invention.

tended for use in any compression ignition engine.

pressed air in the engine cylinder a liquid hydro- 

